Car Dashboard Warning Lights

Check Engine Light - What does it mean?

Car Dashboard Warning Lights

When the electronic-control system finds a problem it cannot adjust, the computer turns on a yellow warning indicator and stores a trouble code in it's memory. These diagnostic trouble codes (DTC) help identify the probable source of the problem, such as a malfunctioning sensor or a misfiring engine and can be read with a scan tool or diagnostic computer. Vehicle manufacturers originally used the OBD system to help technicians pinpoint and troubleshoot malfunctions. Exactly what the OBD system looks for depends on the make, model and year of the vehicle.

The original systems varied widely in their capabilities and some did little more than check whether the various electronic sensors were hooked up and working. With the advent of the OBD II systems, required under federal laws regulating automotive emissions, automakers were required to install a more sophisticated system that, for all intents and purposes, acts like a built-in emissions monitoring station. The check engine light is reserved only for problems that may have an effect on the vehicle emissions systems.

What does it mean?

If the check engine light illuminates, it will either blink or remain constant, depending on the problem. Either way, you should have the vehicle checked by a Qualified Service Technician as soon as possible.

If the light is steady. The problem is not an emergency, but you should schedule an appointment as soon as possible.

A blinking light usually indicates a severe engine misfire allowing unburned fuel to be dumped into the exhaust system. There it can quickly raise the temperature of the catalytic converter to a point where damage is likely, requiring an expensive repair. If this occurs, you should reduce power and have the vehicle checked as soon as possible.

Today's automotive computers often try to compensate when there's a problem: so you may not notice deterioration in performance, even though your fuel mileage is suffering and your vehicle may be emitting unacceptable levels of hydrocarbons and/or other pollutants.

If the check engine light comes on:

Look for a serious problem that requires immediate attention.

Check your dashboard gauges and lights for indications of low oil pressure or overheating. These conditions mean you should pull over and shut off the engine as soon as you can find a safe place to do so.

Try tightening your gas cap.

This often solves the problem. Keep in mind that it may take several trips before the light resets. Some vehicles have a separate indicator that warns of a loose gas cap before the condition sets off the check engine light.

Reduce speed and load.

If the check engine light is blinking or you notice any serious performance problems, such as a loss of power, reduce your speed and try to reduce the load on the engine. For example, it would be a good idea to stop towing a trailer. Have the car checked as soon as possible to prevent expensive damage.